''Proterogyrinus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of early

tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

s from the order Embolomeri. Fossil remains of ''Proterogyrinus'' have been found in Scotland, UK, and

West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...

, United States, and date back to the Serpukhovian (mid-

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

period), which is from about 331 to 323 million years ago. The genus was originally named by renowned vertebrate paleontologist Alfred Sherwood Romer in 1970. A comprehensive redescription was later published by Canadian paleontologist Robert Holmes in 1984. The generic name "''Proterogyrinus''" is

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

for "earlier wanderer" or "earlier

tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

". This name was chosen by Romer in keeping with a trend of naming long-bodied early tetrapods (such as '' Eogyrinus'' and '' Crassigyrinus'') with the suffix "-''gyrinus''". Romer hesitated from designating ''Proterogyrinus'' as a true embolomere, because its intercentra (the forward portion of each vertebra) were smaller than its pleurocentra (the rear portion). He used the group Anthracosauria to encompass embolomeres and their close relatives such as ''Proterogyrinus''. However, other sources prefer a wider definition of Embolomeri similar in usage to Romer's Anthracosauria, thus counting ''Proterogyrinus'' as an embolomere.

Description

In most respects ''Proterogyrinus'' resembled other embolomeres such as '' Archeria'', with a moderately elongated skull that was taller than that of other early tetrapods such as colosteids and temnospondyls. Members of the genus had strong limbs with several fully-

ossified Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

ankle and wrist bones. This would have given ''Proterogyrinus'' the ability to walk and hunt on land. However, the presence of lateral line grooves and

otic notch Otic notches are invaginations in the posterior margin of the skull roof, one behind each orbit. Otic notches are one of the features lost in the evolution of amniotes from their tetrapod ancestors. The notches have been interpreted as part of an ...

es which likely held spiracles show that they were probably more well-adapted for the water. The tail was long and tall, and was likely a powerful method of locomotion. The eyes were positioned high on the skull, supporting the idea that ''Proterogyrinus'' had an active lifestyle near the surface of the water.

References

{{Taxonbar, from=Q134526 Extinct animals of North America Embolomeri Carboniferous reptiliomorphs Transitional fossils Taxa named by Alfred Romer Fossil taxa described in 1970